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Unraveling Ribozymes

Today is the 52nd birthday of Thomas Cech, a biochemist who helped discover catalytic RNA. In the process, Cech and his colleagues overturned conventional wisdom about the interactions between DNA, RNA, and protein enzymes in the evolution and reproduction of life.

Cech wanted to know how the genetic code in DNA is copied to an RNA template--a process called transcription--and how certain parts of the code are spliced out. During an experiment in 1981, Cech and his colleague Arthur Zaug were surprised to learn that protozoan RNA appeared to splice itself without the help of any enzymes. Their announcement in 1982 of the existence of a "ribozyme"--an RNA molecule capable of catalyzing chemical reactions--upset beliefs about the nature of enzymes, but soon other catalytic RNAs were discovered.

The finding bolstered the idea that RNA was the first important biological molecule to arise in the "primordial soup" and to spur the evolution of life. Catalytic RNAs are now being engineered and tested as potential drugs for treating viral infections. Cech received a share of the 1989 Nobel Prize in chemistry. He currently heads a lab at the University of Colorado, Boulder, but was appointed president of the Howard Hughes Medical Institute in Chevy Chase, Maryland this year (ScienceNOW, 24 March), where he will take office on 1 January 2000.